In computer-aided design (“CAD”), designers use computers to model three-dimensional objects to assist in the design and manufacture of parts. To implement these models, CAD programs use surfaces to represent three-dimensional objects. Examples of mathematical surface models include Béziers and Nurbs surfaces. One classical way of defining such surfaces is by means of a network of control points. The control points that control the surface are not necessarily on the surface. FIG. 4 shows an example of a surface and the control points that control the surface. As can be seen, only the control points on the four-corners are on the surface. The other control points affect the surface, but are usually not on the surface.
When surfaces are designed, the surfaces may not be uniform or of high quality. FIG. 1A is an example of a three-dimensional surface defined by points in a network that is not uniform or of high quality.
The shape and smoothness of surfaces is particularly important when the surface is visible in a product. These visible surfaces, such as CLASS_A surfaces, are typically used in vehicle and consumer goods. For example, a car hood is a CLASS_A surface that must be smooth because the smoothness can affect how a potential buyer views the car. When the car is displayed in a car showroom, light reflects off the car hood. If the car hood is smooth and regular, the light reflects in an aesthetically pleasing matter. If the car hood is rough or irregular, the light can reflect in a strange pattern that can negatively affect a potential buyer.
Currently, creating high quality CLASS_A surfaces can require a strong expertise, particularly to obtain a good organization of the control points for these surfaces. This organization can be obtained manually by allowing a designer to manipulate individual points using a user interface and control point handling. The designer can start by amplifying the defects by compressing or changing the sights, or zooming into and out of the surface. After amplifying the defects, the designer usually has to manipulate individual control points in the network of points. The designer then views the surface to determine if it is of sufficient quality. The designer can manipulate the same or other control points, and view the results. The designer can repeat this process until satisfied with the smoothness or uniformity of the surface. As individual control points are changed, unrelated parts of the surface can be negatively affected. The designer usually has to consider this as the designer attempts to increase the quality of the surface. This methodology can be difficult and expensive to implement. This invention addresses some of these issues.